What injury caused Gregory House to use a cane in House M.D.?

A quadriceps muscle infarction caused Gregory House to use a cane in House M.D. The condition damaged muscle in his right thigh after blood flow was blocked, leaving him with chronic pain and impaired movement.

House's leg injury occurred before the series begins. He initially underwent treatment for what was believed to be a clot, but the infarction was not adequately addressed before the muscle tissue became permanently damaged. He later had dead tissue removed, leaving a scar and lasting disability.

The injury explains several important parts of House's characterization: his limp, reliance on a cane, and use of Vicodin for pain. The show reveals more of the history in the episode “Three Stories,” which explores the medical decisions surrounding his leg.

A muscle infarction is different from a bone fracture or a typical tendon tear. The word infarction refers to tissue death caused by inadequate blood supply, making this detail central to understanding House's medical history.